(中南大学 冶金与环境学院，长沙 410083)
摘 要: 采用氧化-水解法从高铁硫酸钴溶液中除铁，再采用水热法对除铁渣进行脱硫转型成赤铁矿的过程。考察双氧水用量、pH值、温度、晶种及添加剂对除铁率、钴损失率，除铁渣粒度、形貌及浆液沉降速度的影响，以及水热温度、时间、NaOH浓度对除铁渣水热转型成赤铁矿中铁、硫含量及物相和形貌的影响。结果表明：双氧水用量1.5倍理论量、pH值2.6、反应温度70 ℃，在此条件下采用半连续-并加法反应4 h，除铁率达到99.68%，钴损失率低至2.87%。添加Fe(OH)3晶种或PAM与PEG2000复配添加剂能大幅提高反应后浆液的沉降速度。对除铁渣进行水热转型，升高温度、延长时间、提高碱浓度均有利于无定型除铁渣向赤铁矿转化。在水热温度230 ℃、水热时间2 h、NaOH浓度40 g/L时，渣中物相全部转化成赤铁矿，铁含量达65.63%，硫含量仅为0.014%。
关键字: 赤铁矿；高铁硫酸钴溶液；氧化水解；除铁；水热转型
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:Iron removal from high-iron cobalt sulfate solution by oxidative hydrolysis, and subsequent hydrothermal conversion of the iron residue into hematite were investigated. The factors influencing iron removal rate, cobalt loss rate and slurry settling speed, such as hydrogen peroxide dosage, pH value, temperature, seeds and additives, were investigated. This study also elucidates the influences of temperature, duration, NaOH concentration on iron and sulfur content, phase and morphology on the treated residue during the hydrothermal conversion process. The results show that, under the optimal conditions of 1.2 times of theoretical amount of H2O2, pH of 2.6, temperature of 70 ℃ and time of 4 h, the iron removal rate can reach 99.68% and the cobalt loss rate is as low as 2.87%. The addition of Fe(OH)3 seeds, PAM and PEG2000 mixed additives can greatly increase the slurry settling performance. Raising temperature, prolonging time and increasing alkali concentration are beneficial to the conversion of amorphous iron hydroxide into hematite. When the hydrothermal temperature is 230 ℃, the hydrothermal duration is 2 h and the NaOH concentration is 40 g/L, the amorphous phase in the iron residue are completely converted into hematite, with iron and sulfur content of 65.63% and 0.014%, respectively.
Key words: hematite; high-iron cobalt sulfate solution; oxidative hydrolysis; iron removal; hydrothermal conversion
